Mitsubishi TV 45"

I have Mitsubishi TV 45" Model # VS-45607, The problem I am having when I'm witching TV for more then 1 HR the TV will change to other channel all by it self, At first I thought it was pretty scarier but now I know it has to be some kind of setting on the TV that need to be change, Does anyone know what I need to do to fix this,

Its not a "setting", its a malfunction.
The tuner is losing channel lock.
Cost more to fix than its worth , sorry.
THE REASON it does it after an hour or so is that it warms up, and the part fails when warm.
And since resistors, capacitors, etc, tend to be pretty hardy, its probably a chip, chip being an electronic term for
A WHEELBARROW FULL OF MONEY.